1. Field of the Invention
The present invention relates to a core material for a fiber reinforced plastic (hereinafter referred to simply as "FRP") and a process for producing the core material.
2. Description of the Prior Art
FRP is widely used as various structural or construction materials such as panels, light weight hull construction material, or hybrid materials. In a case where an extremely high strength is required, the FRP structural material must be made correspondingly thick, which brings about difficulties such that with an increase of the thickness, the structural material becomes heavy and tends to undergo deformation, the production costs will increase and a longer time will be required for the production. In an attempt to overcome such difficulties, a sandwich panel has been proposed in which FRP is bonded to both sides of a light weight core material to form an integral structure.
However, such a sandwich panel is substantially inferior in its strength to a FRP plate having the same thickness. It has an additional drawback that the surface material (i.e. FRP constituting the surface layers) is likely to be separated or peeled off from the core material.